STEMMA moisture sensors/SHT-30

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PoppinBeans
 
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STEMMA moisture sensors/SHT-30

Post by PoppinBeans »

Hey good morning all.

Before I forget to mention it! I’m using an Arduino Uno. Currently in my tents I have some cheapo analog capacitive moisture sensors off Amazon, and they work very well for the price. However, I would like to free up some IOs and purchase the STEMMA I2C moisture sensors, seen here:

https://www.adafruit.com/product/4026?u ... ewproducts

I have 2 plants, and would like a sensor in each. I’m concerned with the addresses of the sensors conflicting. Am I only able to run one sensor with the I2C bus? Or is there a means of changing their addresses?

On another note, how do these sensors compare to the SHT-30 sensors? Seen here:

https://www.adafruit.com/product/4099?g ... GMQAvD_BwE

It looks like I can actually bury the SHT-30 and not worry about water damage. I’m tempted to purchase one of each! The same question lingers with the SHT-30; am I able to run more than one of these sensors on the I2C bus?

Appreciate the help!

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DJDevon3
 
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Re: STEMMA moisture sensors/SHT-30

Post by DJDevon3 »

There are 2 I2C address pads on the back, AD0 and AD1. You can run a maximum of 4 of these moisture sensors on a single board. By soldering pads and simple math you can setup 4 sensors to have a fixed address of 0x36, 0x37, 0x38, or 0x39.

0x36 is the default address with no pads soldered and 0x39 is the address with both pads soldered.
Don’t solder anything to keep the default address. (0x36)
Solder AD0 to add 1 to the address (0x37)
Solder AD1 to add 2 to the address (0x38)
Solder AD0 and AD1 to add 3 to the address (0x39)

https://learn.adafruit.com/adafruit-ste ... or/pinouts

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DJDevon3
 
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Re: STEMMA moisture sensors/SHT-30

Post by DJDevon3 »

The SHT3x sensors are humidity sensors not soil moisture sensors. They are functionally different. You do not want to bury a humidity sensor as it detects moisture in the air and is far more sensitive. You would flood a moisture sensor if you put it in direct contact with soil or water. It wouldn't function for your intention.

If you want a moisture sensor for direct soil contact then go with a capacitive sensor like the Adafruit Stemma Soil Moisture Sensor.

Keep in mind soil types are different so you will have to calibrate the code a little to optimize it for your soil type.

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